As shown in FIG. 1, a prior art digital connector is illustrated. The digital connector includes an insulating body 10a, a metal casing 11a, two buckles 12a, two positioning piece 13a, and two retaining pieces 14a. The insulating body 10a is made of plastics and other insulating materials, and two sides thereof each are installed with a through hole 15a for receiving the two retaining pieces 14a. The metal casing 11a is an iron casing and made by punching. The metal casing is installed in front of the insulating body 10a. Two sides of the metal casing 11a are installed with through holes 16a which is correspondent to the through holes 15a of the insulating body 10a. The two buckles 12a are installed at two sides of the insulating body 10a. The upper end of each buckle 12a is formed with a through hole 17a. The two positioning pieces 13a each are installed with a through hole 18a. The two retaining pieces 14a are matched to the through holes 16a, 15a, 17a, and 18a of the metal casing 11a, insulating body 10a, two buckles 12a and two positioning pieces 13a. The front end and rear end of the two retaining pieces 14a are riveted so that the front end and rear end of the retaining piece 14a are connected to the metal casing 11a and positioning piece 13a by riveting connection. Thus, the insulating body 10a, metal casing 11a, two buckles 12a and two positioning pieces 13a are firmly secured as an integral body. Thereby, the metal casing 11a and two buckles 12a are fixed to the insulating body 10a. The lower end of each two buckles 12a has a buckling portion 19a for being engaged to the circuit board. The metal casing 11a covers on the outer side of the inserting portion 20a of the insulating body 10a. Two screw means 21a serve to be screwedly connected within the two retaining pieces 14a for being fixed to the front end of the metal casing 11a. A plurality of channels 22a are installed within the insulating body 10a. Each channel 22a is matched with a conductive terminal (not shown). The lower end of the conductive terminal protrudes out of the bottom of the insulating body 10a so as to be electrically connected to a circuit board.
However, in aforesaid prior art digital connector, as the two retaining pieces 14a are connected to the metal casing 11a and positioning pieces 13a by riveting connection, a stress force will generate so that the outer portions 23a of two through holes 15a of the insulating body 10a will crack and thus the yield ratio of the product is decreased greatly. Therefore, the manufacturing cost can not be reduced. If it is want to avoid this event, it is needed to increase the thickness of the outer portion 23a of two through holes 15a, but this will cause that the whole width and volume of the connector are increased. Other than more plastic materials are required, it remain not to meet the requirement of compact of current trend.